Applied Mechanics and Materials Vols. 184-185

Abstract: The large ellipsoidal aluminium plate system for missile in lab simulation[2], reaching a length of nearly 100 meters, is an important component of the laboratory. How to make it well-designed to avoid repetition and reduce the loss is the key to the project. This paper proposes the calculation methods andmodels for the geometrical parameters such as longitude and latitude line length, radius of curvature , keel curve direction on ellipsoid and deflecting ellipsoid. The practical problem is resolved successfully by designing the calculation models.

Abstract: In bridge structural health monitoring, random vibration test and monitoring bridge dynamic characteristics provides an effective method for evaluation of bridge safety and serviceability performance. Piezoelectric accelerometer overcome the draw backs of the traditional sensor characteristic measuring instrument which are functional singleness and monopoly used, a piezoelectricity acceleration sensor performance analysis and dynamic characteristics monitoring system base on a tied arch bridge health monitoring system was designed, and the hardware structure and software of the system were introduced, acquired vibration signal can be displayed, stored, analyzed and processed in real time. The vibration frequency of the bridge structure, mode shapes and damping ratio is calculated base on the monitoring data, and the amplitude of frequency domain shows that the system was validated in actual real-time monitoring of bridge dynamic characteristics.

Abstract: The heavy oil is the key point which China develops, at present the heavy oil is produced using the technique of blending light dropping viscosity, in addition to usual tubing failure ( pull out, fracture, perforation, corrosion etc.), a new failure form appeared that is tubing collapse, especially in western oilfields China. For the tubing collapse failure in heavy oil recovery well, this paper used the method which the experiment and the theory unify to launch on the analysis research, and mainly considered and analyzed tubing collapse strength under two kind of operating condition according to the field operation situation. This paper pointed out that should consider the bending effect in the pipe string design and the field operation, and must carry on the preliminary calculation to the anti-extrusion pressure in front of the field operation, in order to control the biggest anti-extrusion pressure in the annulus.

Abstract: Ship modeling is more complicated than any other artificial architecture according to its complicated structure, anomalous formation, all types of surface. Based on analysis on the hull, we studied the skills and methods with three views and lofting technique on the platform of 3ds MAX. Firstly, collect detail parameters and views from Internet, then preprocess orthographic views before establishing reference hull and fragmented curves by lofting technique. At last a complete ship model by combing hull and weapons is established. The simulation result is lifelike; it can provide an attractive experiment environment for Virtual Reality, Object Recognition, Engineering Analysis, etc.

Abstract: Focusing on the problems of the bamboo plywood existing in the construction field, we have proposed an optimal process for the building bamboo plywood through controlling the preparation process of the bamboo plywood. In our work, moso bamboo was selected as the objective and then a variety of performances of the bamboo plywood were tested with the heat-up-heat-down process. Experiments show that in the same conditions of MC 10%, RC 7%-8%, the best optimum processes of 12mm thick constructional bamboo plywood is 15min pressing time, the pressing temperature between 155°C to 160°C and the sheet density of 0.85 g/cm3. The optimal process to make the performance of bamboo plywood substantially exceeded the European standard the OSB/4 levels. It can provide practical application of engineering and production design with reference value and theoretical basis for the bamboo plywood.

Abstract: In modern steel production, strip products account for more than half of the total output. Roll eccentricity is ubiquitous in strip mills, which has a periodic impact on the strip thickness difference. Roll eccentricity compensation is an important part of the automatic gauge control system. Most roll eccentricity compensations extract the roll eccentricity based on the frequency domain analysis of the rolling force. It is difficult to ensure measurement precision of roll eccentricity due to the complexity of interference of the rolling force, therefore the compensation accuracy is difficult to ensure. The roll eccentricity extraction method, based on comprehensive signal processing, was introduced in this paper combined with engineering practice. The roll eccentricity was comprehensively calculated by thickness gauge and other signals that have been delayed; the roll phases were calculated by the roll rotational displacement; and finally, the roll eccentric fluctuation of the upper backup roll and lower backup roll were extracted. The roll eccentricity could be predicted by calculating roll eccentric fluctuations and phases, in order to provide the basis for accurate compensation. According to the comparison with roll eccentricity extracted by the frequency domain analysis of the rolling force, the roll eccentricity obtained by the roll eccentricity extraction method, based on comprehensive signal processing, is more accurate. It provides a reliable basis for roll eccentricity compensation in order to improve the accuracy of the thickness of the strip products.

Abstract: A detailed analysis of the concept of strain energy density and strain gradient on the material microscale effect in a micro-machined gyroscope is carried out. By analysis, the material microscale effect mainly influences its elastic modulus. The analytical expression of the valid elastic modulus on the micro elastic beam structure of the micro-machined gyroscope is deduced. When considering the valid elastic modulus and not, respectively compare the natural frequency of the elastic beam with the actual measurement results. The error of former is far less than the latter. By the theoretical derivation and experiment test, the influence of the material microscale effect on the micro-machined gyroscope is analyzed.

Abstract: Oil source made up of constant pressure variable displacement pump, accumulator, and pipeline is widely used to provide stable pressure for electro-hydraulic control system in practical engineering. The control system is non-linear and real-time, each part of which is interactive, a simulation model of energy source system is built, which includes constant pressure pump, accumulator and pipeline and load by means of AMESim software. Based on the simulation and experiment, the relationship between the load frequency variation and the pressure fluctuation of oil-source are obtained, the research provides support on how to confirm the equipment parameter properly, improve the stability of energy source system and enhance the control precision by reasonable confirming the equipment parameter.

Abstract: In order to estimate the damping consumption of traditional suspension, this paper established the tracked vehicle model based on the dynamic simulation software RecurDyn, and the road models of B、D and F grad are constructed by harmony superposition method. Through the simulation of the suspension vibration, the relation between suspension consumption and different road surface and velocity is performed. The results supply some reference for the research on regenerative-energy suspension of tracked vehicle.

Abstract: Braking deceleration of passenger-car has great influence on the pedestrian motion process after collision of human-vehicle accident, but it is considered not enough in current accident reconstruction and vehicle-speed analysis. In order to improve the accuracy of accident reconstruction, a computer simulation model of pedestrian-vehicle accidents based on finite element (FE) method and human parameters of Chinese adult human body is established. In this article, based on the FE model, human-vehicle crash is simulated through involving the influence of braking deceleration of passenger-car. For the application of the vehicle-speed analysis, the motion performance of pedestrian after collision were studied and the correlation between the pedestrian throw distance and vehicle impact speed are investigated. The influence of braking deceleration in same impact speed is analyzed. Research results show that the vehicle brake deceleration has a certain influence on the throw distance of pedestrian and it should be taken into account on the accident reconstruction. We can conclude that pedestrian throw distance can be used to estimate the vehicle collision speed accurately when drivers take full braking measure during the crash.